KR100829312B1 - Control method for preventing a backward moving of hybrid electric vehicles in slope - Google Patents

Abstract

A control method for preventing a hybrid electric vehicle from moving backward on the slope is provided to restrain the starting delay and backward movement of the vehicle by turning on a CAS(Creeping Aided System) for certain time if an engine is turned on and driving the CAS by adding the starting completion time to the certain time if the engine is turned off. In a control method for preventing a hybrid electric vehicle equipped with a CAS from moving backward on the slope, the CAS operating time is set differently according to starting state judgment conditions if the vehicle starts again after stopping on the slope. The starting state judgment condition indicates whether the vehicle is in an idle stop state or not. If not the idle stop state, the CAS operating time is determined as T1 after brake-off, when the vehicle starts after stopping while starting an engine. In case of the idle stop state, the CAS operating time is determined as T2 relatively longer than T1 after brake-off, when the vehicle starts after stopping while the engine is not started.

Description

Control method for preventing a backward moving of hybrid electric vehicles in slope}

1 is a flowchart illustrating a method of controlling a rolling back of a hill road of a hybrid electric vehicle according to an exemplary embodiment of the present invention.

The present invention relates to a hillside backward control method of a hybrid electric vehicle, and more particularly, by varying the operating time of the CAS depending on whether or not the vehicle having the idle stop function restarts after stopping at the hillside when the vehicle is in the idle stop state In addition, the present invention relates to a hillside backside prevention control method of a hybrid electric vehicle, which can prevent the delay of departure and backside phenomenon of a vehicle.

Transmission (T / M) with a clutch has no clutch power when the brake is on and the engine is open, and when the brake is off, the clutch is engaged. ) To transmit power.

At this time, when the vehicle is restarted after stopping at the slope, a phenomenon in which the vehicle is pushed backward when sufficient power is not transmitted to the wheel.

Meanwhile, the conventional hybrid vehicle has an idle stop function for turning off the engine when the vehicle is stopped to improve fuel efficiency.

The idle stop mode is operated even when the vehicle is stopped while driving on a slope, and the vehicle is started by the driver's intention to restart, that is, the brake off, and the engine RPM is increased to complete the engine start time and CVT clutch. It takes a time of about 1 to 2 seconds, at which time the vehicle is pushed backwards has a problem that occurs.

 In order to solve the above problems, the hybrid vehicle is equipped with a CAS (Creeping Aided System), and by turning on the CAS for a certain time from the brake off time, so that the brake hydraulic pressure is maintained for a certain time independently of the driver's brake signal. The control prevents the rearward sliding.

In the case of the hybrid vehicle, the operating time of the CAS depends on the inclination obtained from the inclination angle sensor, and the CAS operating time in the idle stop state is the same as the CAS operating time in the non-idle stop state under some conditions. To be controlled.

However, since the engine is turned off in the idle stop state, it takes a long time for the engine power to be transmitted to the drive shaft by the engine start completion time when starting.

 Therefore, if the CAS operating time does not depend on whether the engine is started or not, the CAS will be operated for a long time unnecessarily when the engine is on. It can be short enough to cause a push on the hill.

The present invention has been made in view of the above, and when starting from a stopped state of the vehicle when driving on a hill road, it is determined whether the engine is turned off or the engine is turned on by the idle stop condition, and the engine is turned on. In the case of, the driving of the CAS is turned on for a predetermined time (T1), and in the case of the starting-off state, the driving of the CAS is driven by adding the starting completion time to the predetermined time (T1), thereby delaying the starting delay and the backward drift on the hill. It is an object of the present invention to provide a control method for preventing rolling behind hill roads of a hybrid electric vehicle.

In the present invention for achieving the above object in the hill trail back control method of a hybrid electric vehicle equipped with CAS,

When the vehicle restarts after stopping at the hill road, the CAS operating time may be set differently depending on whether the starting condition determination condition is satisfied.

In a preferred embodiment, the starting condition determination condition is to determine whether the idle stop state or not the idle stop state, and if the idle stop state is not after the brake off when the vehicle starts after stopping in the starting state The CAS operating time is T1, and in the idle stop state, the CAS operating time after the brake-off when the vehicle starts after stopping in the state where the start is not applied is characterized in that T2 is relatively longer than T1.

In a more preferred embodiment, the starting condition determination condition is to determine whether to start the engine without using T2, it is characterized in that to operate the CAS by T1 after the start is completed.

In particular, in the case of the continuously variable transmission, the start state determination condition is determined by determining whether the engine can be started without using T2 in the case of a continuously variable transmission, and determining a state in which the vehicle can start, such as generating a continuously variable transmission hydraulic pressure even after the startup is completed. Afterwards, the CAS is operated as much as T1.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a method of controlling a rolling back of a hill road of a hybrid electric vehicle according to an exemplary embodiment of the present invention.

The hill trail back control method of the hybrid electric vehicle according to an embodiment of the present invention is applied by varying the operating time of the CAS depending on the idle stop during hill road driving, to prevent the start delay and the back fall phenomenon There is this.

In order to prevent the back of the vehicle when driving on a hill, the CAS operates when the brake is turned off or when the vehicle is braked and the vehicle is stationary so that the brake hydraulic pressure is maintained at a constant level independently of the driver's brake signal when the vehicle is restarted. do.

1. Determine whether CAS is running

First, it is determined whether the CAS is driven.

2. Determination of brake on / off status

When the driver stops while driving on a hill, the driver can sense the intention to start with the brake pedal sensor. When the driver receives the brake on / off signal from the brake pedal sensor, the driver determines that the vehicle is in the stopped state and brakes. In the off state, it is determined that the vehicle intends to start.

At this time, since the brake hydraulic pressure is operated by the brake operating signal when the brake is on, it is possible to prevent the back of the hill road without driving the CAS separately. Therefore, the CAS operation judgment time T is set to zero.

The problem is when the brake operation signal is turned off by releasing the brake pedal, and the brake hydraulic pressure can maintain the same effect as applying the brake by the operation of the CAS. At this time, the operation determination time of the CAS is calculated. The operation determination time becomes T = T + 1 if the period from the start to the end of this embodiment is 1 ms and the period from the calculation of the CAS operation time to the calculation of the next CAS operation time is also 1 ms.

3. Determination of Children Stop

The idle stop determination is to determine whether the engine startup is on or off in the vehicle stop state.

That is, when starting with the engine started on (the idle stop function not activated), the CAS operating time after brake off is T1, and when starting with the engine started off (the idle stop function activated). Since the CAS start time after brake off has to be added to the start completion time for starting, the CAS run time after break off is T2 which is relatively longer than T1.

Since the T1 is in a state in which the brake hydraulic pressure is not operated for a time from the start of the engine to the time when the engine power is transmitted to the drive shaft after the brake off, the CAS must be operated to prevent the back of the vehicle from being pushed back. In addition, T1 has inclination information received from the inclination angle sensor, etc., and the higher the inclination, the larger the value.

Therefore, when the CAS operation judgment time (T) calculated above is less than T1 or T2, continue to turn on the CAS to maintain brake hydraulic pressure to prevent slippage, and when CAS operation determination time (T) is greater than T1 or T2, turn off the CAS. Release the flake hydraulic pressure.

If T2 is not used and the engine is started or not, if the start is not completed, the time when T1 is added to the time when the start is completed is the operating time of CAS. It can work.

In addition, the CVT requires a hydraulic generation time for the operation of the CVT after starting. Therefore, in the condition that the vehicle is not started, such as the generation of CVT hydraulic pressure in addition to the engine start condition under the condition that T2 is not used, it is determined that the vehicle is stopped instead of the idle stop, and the CAS is operated by T1 after the start state is completed. You can do that.

In this way, by varying the CAS operating time according to the idle stop conditions, it is possible to prevent the start delay and the rolling of the vehicle.

While the invention has been shown and described with respect to certain preferred embodiments thereof, the invention is not limited to these embodiments, and has been claimed by those of ordinary skill in the art to which the invention pertains. It includes all the various forms of embodiments that can be carried out without departing from the spirit.

As described above, according to the method for preventing hill back rolling of the hybrid electric vehicle according to the present invention, when starting from the stopped state of the vehicle when driving on the hill, whether the engine is turned off by the idle stop condition or the engine is turned on It is judged whether or not the state is turned on, and the driving of the CAS is turned on for a predetermined time (T1) in the case of the start-up state, and the driving of the CAS is driven by adding the start completion time or the like to the predetermined time (T1) in the case of the starting-off state Delays in departures and backwards on hillsides can be prevented.

Claims (4)

In the hill trail backward control method of a hybrid electric vehicle equipped with a CAS, A method for preventing hill back rolling of a hybrid electric vehicle, wherein the CAS operation time is set differently depending on whether the starting condition determination condition is satisfied when the vehicle is restarted after stopping at the hill road. The method according to claim 1, The starting condition determination condition is to determine whether the idle stop state or not the idle stop state, and if the idle stop state, the CAS operating time after the brake off when the vehicle starts after stopping in the starting state is T1 And, in the idle stop state, when the vehicle starts after stopping in the state where the start is not started, the CAS operating time after the brake-off is T2, which is relatively longer than T1. The method according to claim 2, The starting condition determination condition is to determine whether to start the engine without using T2, after the start is completed, the rolling control of the hill behind the hybrid electric vehicle, characterized in that for operating the CAS by T1. The method according to claim 2, The starting condition determination condition is to determine whether to start the engine without using T2 in the case of continuously variable transmission, and to determine whether the vehicle can start, such as generating a continuously variable transmission hydraulic pressure even after the start is completed, and after completion of the starting state determination, T1. Hill road backward control method of the hybrid electric vehicle, characterized in that for operating the CAS.

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